U.S. patent application number 17/540154 was filed with the patent office on 2022-07-28 for redundant parallel mechanism with less actuation and multi-degree-of-freedom outputs and control method thereof.
The applicant listed for this patent is YANSHAN UNIVERSITY. Invention is credited to PENGYANG GAO, SHENGLONG NIE, XIAOYU PANG, YUNDOU XU, YIMING ZHANG, YONGSHENG ZHAO.
Application Number | 20220234192 17/540154 |
Document ID | / |
Family ID | 1000006050197 |
Filed Date | 2022-07-28 |
United States Patent
Application |
20220234192 |
Kind Code |
A1 |
XU; YUNDOU ; et al. |
July 28, 2022 |
REDUNDANT PARALLEL MECHANISM WITH LESS ACTUATION AND
MULTI-DEGREE-OF-FREEDOM OUTPUTS AND CONTROL METHOD THEREOF
Abstract
A redundant parallel mechanism with less actuation and
multi-degree-of-freedom outputs and a control method thereof are
provided, which relate to the field of robot mechanisms. The
redundant parallel mechanism includes: a fixed platform, a moving
platform, multiple moving branch chains, and one or more redundant
branch chains. Two ends of each moving branch chain are
respectively connected to the fixed platform and the moving
platform, and a brake is arranged on each moving branch chain. Two
ends of each redundant branch chain are respectively connected to
the fixed platform and the moving platform, and an actuating part
is arranged on each redundant branch chain. There are n redundant
branch chains arranged. During control, the number of follow-up
moving branch chains is set to n, and the n moving branch chains
move to expected positions and postures under the control of the n
redundant branch chains.
Inventors: |
XU; YUNDOU; (Qinhuangdao
City, CN) ; ZHANG; YIMING; (Qinhuangdao City, CN)
; ZHAO; YONGSHENG; (Qinhuangdao City, CN) ; PANG;
XIAOYU; (Qinhuangdao City, CN) ; NIE; SHENGLONG;
(Qinhuangdao City, CN) ; GAO; PENGYANG;
(Qinhuangdao City, CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
YANSHAN UNIVERSITY |
Qinhuangdao City |
|
CN |
|
|
Family ID: |
1000006050197 |
Appl. No.: |
17/540154 |
Filed: |
December 1, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B25J 9/0054
20130101 |
International
Class: |
B25J 9/00 20060101
B25J009/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 28, 2021 |
CN |
202110116056.3 |
Claims
1. A redundant parallel mechanism with less actuation and
multi-degree-of-freedom outputs, the redundant parallel mechanism
comprising: a fixed platform, a moving platform, a plurality of
moving branch chains, and one or more redundant branch chains,
wherein two ends of each of the moving branch chains are
respectively connected to the fixed platform and the moving
platform, and a brake is arranged on each of the moving branch
chains; and two ends of each of the one or more redundant branch
chains are respectively connected to the fixed platform and the
moving platform, and an actuating part is arranged on each of the
one or more redundant branch chains.
2. The redundant parallel mechanism with less actuation and
multi-degree-of-freedom outputs according to claim 1, wherein each
of the one or more redundant branch chains comprises a first
connecting piece, a first upper connecting rod, a second connecting
piece, a first lower connecting rod, and a third connecting piece
connected in sequence from top to bottom; an upper end of the first
upper connecting rod is connected to the moving platform through
the first connecting piece; and a lower end of the first lower
connecting rod is connected to the fixed platform through the third
connecting piece.
3. The redundant parallel mechanism with less actuation and
multi-degree-of-freedom outputs according to claim 2, wherein each
of the moving branch chains comprises a fourth connecting piece, a
second upper connecting rod, a fifth connecting piece, a second
lower connecting rod, and a sixth connecting piece connected in
sequence from top to bottom; an upper end of the second upper
connecting rod is connected to the moving platform through the
fourth connecting piece; and a lower end of the second lower
connecting rod is connected to the fixed platform through the sixth
connecting piece.
4. The redundant parallel mechanism with less actuation and
multi-degree-of-freedom outputs according to claim 3, wherein both
the first connecting piece and the third connecting piece are
spherical joints; the second connecting piece is a prismatic joint;
the actuating part is mounted on the second connecting piece; and
the actuating part is a linear actuating unit.
5. The redundant parallel mechanism with less actuation and
multi-degree-of-freedom outputs according to claim 4, wherein both
the fourth connecting piece and the sixth connecting piece are
spherical joints; the fifth connecting piece is a prismatic joint;
the brake is mounted on the fifth connecting piece.
6. The redundant parallel mechanism with less actuation and
multi-degree-of-freedom outputs according to claim 4, wherein the
fourth connecting piece is a spherical joint; the fifth connecting
piece is a prismatic joint; the sixth connecting piece is a
revolute joint; and the brake is mounted on the fifth connecting
piece.
7. The redundant parallel mechanism with less actuation and
multi-degree-of-freedom outputs according to claim 3, further
comprising a constraint branch chain, wherein a lower end of the
constraint branch chain is fixedly connected to a center of the
fixed platform; an upper end of the constraint branch chain is
connected to a center of the moving platform through an universal
joint; both the first connecting piece and the fourth connecting
piece are spherical joints; both the second connecting piece and
the fifth connecting pieces are universal joints; both the third
connecting piece and the sixth connecting piece are revolute
joints; the actuating part is mounted on the third connecting
piece; the actuating part is a rotary actuating unit; and the brake
is mounted on the sixth connecting piece.
8. A control method for the redundant parallel mechanism with less
actuation and multi-degree-of-freedom outputs, the control method
comprising: enabling one or more redundant branch chains to
comprise n redundant branch chains, releasing a brake of each of
first n moving branch chains of the moving branch chains, such that
the first n moving branch chains are in a follow-up state; locking
the brake of each of other moving branch chains of the moving
branch chains, such that the other moving branch chains are in a
locked state; adjusting displacements of the first n moving branch
chains by controlling an actuating input of the n redundant branch
chains; enabling (n+1)th to 2nth moving branch chains of the moving
branching chains to be in the follow-up state, and locking
remaining moving branch chains, adjusting displacements of the
(n+1)th to 2nth moving branch chains by controlling the actuating
input of the n redundant branch chains; and enabling adjustments of
the moving branch chains to be realized by repeating above
steps.
9. The control method for the redundant parallel mechanism with
less actuation and multi-degree-of-freedom outputs according to
claim 8, wherein each of the one or more redundant branch chains
comprises a first connecting piece, a first upper connecting rod, a
second connecting piece, a first lower connecting rod, and a third
connecting piece connected in sequence from top to bottom; an upper
end of the first upper connecting rod is connected to the moving
platform through the first connecting piece; and a lower end of the
first lower connecting rod is connected to the fixed platform
through the third connecting piece.
10. The control method for the redundant parallel mechanism with
less actuation and multi-degree-of-freedom outputs according to
claim 9, wherein each of the moving branch chains comprises a
fourth connecting piece, a second upper connecting rod, a fifth
connecting piece, a second lower connecting rod, and a sixth
connecting piece connected in sequence from top to bottom; an upper
end of the second upper connecting rod is connected to the moving
platform through the fourth connecting piece; and a lower end of
the second lower connecting rod is connected to the fixed platform
through the sixth connecting piece.
11. The control method for the redundant parallel mechanism with
less actuation and multi-degree-of-freedom outputs according to
claim 10, wherein both the first connecting piece and the third
connecting piece are spherical joints; the second connecting piece
is a prismatic joint; the actuating part is mounted on the second
connecting piece; and the actuating part is a linear actuating
unit.
12. The control method for the redundant parallel mechanism with
less actuation and multi-degree-of-freedom outputs according to
claim 11, wherein both the fourth connecting piece and the sixth
connecting piece are spherical joints; the fifth connecting piece
is a prismatic joint; the brake is mounted on the fifth connecting
piece.
13. The control method for the redundant parallel mechanism with
less actuation and multi-degree-of-freedom outputs according to
claim 11, wherein the fourth connecting piece is a spherical joint;
the fifth connecting piece is a prismatic joint; the sixth
connecting piece is a revolute joint; and the brake is mounted on
the fifth connecting piece.
14. The control method for the redundant parallel mechanism with
less actuation and multi-degree-of-freedom outputs according to
claim 10, further comprising a constraint branch chain, wherein a
lower end of the constraint branch chain is fixedly connected to a
center of the fixed platform; an upper end of the constraint branch
chain is connected to a center of the moving platform through an
universal joint; both the first connecting piece and the fourth
connecting piece are spherical joints; both the second connecting
piece and the fifth connecting pieces are universal joints; both
the third connecting piece and the sixth connecting piece are
revolute joints; the actuating part is mounted on the third
connecting piece; the actuating part is a rotary actuating unit;
and the brake is mounted on the sixth connecting piece.
Description
CROSS REFERENCE TO RELATED APPLICATION
[0001] This patent application claims the benefit and priority of
Chinese Patent Application No. 202110116056.3 filed on Jan. 28,
2021, the disclosure of which is incorporated by reference herein
in its entirety as part of the present application.
TECHNICAL FIELD
[0002] The present disclosure relates to the technical field of
robot mechanisms, and in particular, to a redundant parallel
mechanism with less actuation and multi-degree-of-freedom outputs
and a control method thereof.
BACKGROUND ART
[0003] Parallel mechanisms have the advantages of compact
structure, large bearing capacity, high accuracy, and small retrace
error and so on, and are widely used in the fields of aerospace,
ships, automobiles, etc. In heavy load conditions, redundant branch
chains need to be added to improve the bearing capacity of the
parallel mechanism, so a redundant actuation parallel mechanism is
proposed. For example, a redundant actuation parallel polishing
robot with five degrees of freedom disclosed in patent
CN201610494181.7 includes a fixed platform, a moving platform, six
RUS actuating branches, and one constraint branch. The overall
mechanism has the advantages by using a redundant parallel
structure as follows: the rigidity is improved, a singularity
posture is avoided, and the working space is effectively increased,
so as to achieve the effect of improving the quality of a machined
surface by the polishing robot. A redundant actuation parallel
robot for friction stir welding disclosed in patent
CN201610289804.7 includes a moving platform, a machine frame, and
four branches connected between the machine frame and the moving
platform. The mechanism can perform the spatial motion with three
degrees of freedom, which has two rotations and one movement, and
has the advantages of high machining precision, high rigidity,
simple accompanying motion, etc. A structural redundant parallel
robot mechanism with three relative degrees of freedom disclosed in
patent CN201710914676.5 includes a base and first to fourth branch
chain components; and the mechanism can perform the spatial motion
with three degrees of freedom, which has two movements and one
rotation, so that the singularity posture of the mechanism is
reduced and the force transmission performance of the mechanism is
improved. However, the number of the actuators of these mechanisms
is greater than the number of degrees of freedom, so they are more
difficult to be controlled cooperatively, and engineering
application is not easy to realize.
SUMMARY
[0004] In order to solve the above technical problem, some
embodiments provide a redundant parallel mechanism with less
actuation and multi-degree-of-freedom outputs and a control method
thereof, which reduces actuating parts, reduces the cost and the
control difficulty, and has large bearing capacity.
[0005] To achieve the above objective, some embodiments provide the
following solution.
[0006] The present disclosure provides a redundant parallel
mechanism with less actuation and multi-degree-of-freedom outputs,
the redundant parallel mechanism including a fixed platform, a
moving platform, multiple moving branch chains, and one or more
redundant branch chains, where two ends of each of the moving
branch chains are respectively connected to the fixed platform and
the moving platform, and a brake is arranged on each of the moving
branch chains; and two ends of each of the one or more redundant
branch chains are respectively connected to the fixed platform and
the moving platform, and an actuating part is arranged on each of
the one or more redundant branch chains.
[0007] Preferably, each of the one or more redundant branch chains
includes a first connecting piece, a first upper connecting rod, a
second connecting piece, a first lower connecting rod, and a third
connecting piece connected in sequence from top to bottom; an upper
end of the first upper connecting rod is connected to the moving
platform through the first connecting piece; and a lower end of the
first lower connecting rod is connected to the fixed platform
through the third connecting piece.
[0008] Preferably, each of the moving branch chains includes a
fourth connecting piece, a second upper connecting rod, a fifth
connecting piece, a second lower connecting rod, and a sixth
connecting piece connected in sequence from top to bottom; an upper
end of the second upper connecting rod is connected to the moving
platform through the fourth connecting piece; and a lower end of
the second lower connecting rod is connected to the fixed platform
through the sixth connecting piece.
[0009] Preferably, both the first connecting piece and the third
connecting piece are spherical joints; the second connecting piece
is a prismatic joint; the actuating part is mounted on the second
connecting piece; and the actuating part is a linear actuating
unit.
[0010] Preferably, both the fourth connecting piece and the sixth
connecting piece are spherical joints; the fifth connecting piece
is a prismatic joint; the brake is mounted on the fifth connecting
piece.
[0011] Preferably, the fourth connecting piece is a spherical
joint; the fifth connecting piece is a prismatic joint; the sixth
connecting piece is a revolute joint; and the brake is mounted on
the fifth connecting piece.
[0012] Preferably, the redundant parallel mechanism with less
actuation and multi-degree-of-freedom outputs according to claim ,
further including a constraint branch chain, where a lower end of
the constraint branch chain is fixedly connected to a center of the
fixed platform; an upper end of the constraint branch chain is
connected to a center of the moving platform through an universal
joint; both the first connecting piece and the fourth connecting
piece are spherical joints; both the second connecting piece and
the fifth connecting pieces are universal joints; both the third
connecting piece and the sixth connecting piece are revolute
joints; the actuating part is mounted on the third connecting
piece; the actuating part is a rotary actuating unit; and the brake
is mounted on the sixth connecting piece.
[0013] The present disclosure further provides a control method for
the redundant parallel mechanism with less actuation and
multi-degree-of-freedom outputs, the control method including:
enabling the one or more redundant branch chains to include n
redundant branch chains, releasing the brake of each of first n
moving branch chains of the moving branch chains, such that the
first n moving branch chains are in a follow-up state; locking the
brake of each of other moving branch chains of the moving branch
chains, such that the other moving branch chains are in a locked
state; and adjusting displacements of the first n moving branch
chains by controlling an actuating input of the n redundant branch
chains; enabling n+1th to 2nth moving branch chains of the moving
branching chains to be in the follow-up state, and locking
remaining moving branch chains, adjusting displacements of the
n+1th to 2nth moving branch chains by controlling the actuating
input of the n redundant branch chains; enabling adjustments of the
moving branch chains to be realized by repeating above steps.
[0014] Compared with the prior art, some embodiments achieve the
following technical effects.
[0015] According to the redundant parallel mechanism with less
actuation and multi-degree-of-freedom outputs and a control method
thereof provided by the present disclosure, the redundant parallel
mechanism with less actuation and multi-degree-of-freedom outputs
includes: a fixed platform, a moving platform, multiple moving
branch chains, and one or more redundant branch chains. Two ends of
each moving branch chain are respectively connected to the fixed
platform and the moving platform, and the brake is arranged on each
moving branch chain. The two ends of each redundant branch chain
are respectively connected to the fixed platform and the moving
platform, and the actuating part is arranged on each redundant
branch chain. The number of the redundant branch chains is set to
n, during control, the number of follow-up moving branch chains is
set to n. Except for the follow-up moving branch chains, the other
moving branch chains are locked by the respective brakes. The n
follow-up moving branch chains move to expected positions and
postures under the control of the n redundant branch chains.
Through multiple adjustments, all moving branch chains move to the
expected positions and postures. That is, the control of the
outputs of all expected degrees of freedom of the parallel
mechanism can be realized. It can be seen that the redundant
parallel mechanism of some embodiments has large bearing capacity,
the actuating parts thereof are decreased, the cost thereof is
reduced, thereby realizing multidimensional independent outputs
through multiple actuating, further realizing the adjustment of the
position and posture of the mechanism, and simplifying the control
of a redundant parallel mechanism. Therefore, the mechanism has a
very broad application prospect.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to more clearly illustrate technical solutions in
the embodiments of the present application or in the prior art, a
brief introduction to the accompanying drawings required for the
embodiment will be provided below. Obviously, the accompanying
drawings in the following description are only some of the
embodiments of the present disclosure. Those of ordinary skill in
the art would also be able to derive other drawings from these
drawings without making creative efforts.
[0017] FIG. 1 is a schematic structural diagram of Embodiment 1 of
a redundant parallel mechanism with less actuation and
multi-degree-of-freedom outputs provided by the present
disclosure;
[0018] FIG. 2 is a schematic structural diagram of Embodiment 2 of
a redundant parallel mechanism with less actuation and
multi-degree-of-freedom outputs provided by the present
disclosure;
[0019] FIG. 3 is a schematic structural diagram of Embodiment 3 of
a redundant parallel mechanism with less actuation and
multi-degree-of-freedom outputs provided by the present disclosure;
and
[0020] FIG. 4 is a schematic structural diagram of Embodiment 4 of
a redundant parallel mechanism with less actuation and
multi-degree-of-freedom outputs provided by the present
disclosure.
[0021] Reference signs in the drawings: 100 redundant parallel
mechanism with less actuation and multi-degree-of-freedom outputs;
1 fixed platform; 2 moving platform; 3 redundant branch chain; 301
first upper connecting rod; 302 first lower connecting rod; 303
first connecting piece; 304 second connecting piece; 305 third
connecting piece; 306 actuating part; 4 moving branch chain; 401
second upper connecting rod; 402 second lower connecting rod; 403
fourth connecting piece; 404 fifth connecting piece; 405 sixth
connecting piece; 406 brake; and 5 constraint branch chain.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0022] The technical solutions in the embodiments of the present
disclosure will be clearly and completely described below in
conjunction with the accompanying drawings in the embodiments of
the present disclosure. Apparently, the described embodiments are
only a part of the embodiments of the present disclosure, rather
than all the embodiments. Based on the embodiments of the present
invention, all other embodiments obtained by those of ordinary
skill in the art without creative work shall fall within the
protection scope of the present invention.
[0023] An objective of some embodiment is to provide a redundant
parallel mechanism with less actuation and multi-degree-of-freedom
outputs and a control method thereof, which reduces actuating
parts, reduces the cost, reduces the control difficulty, and has
large bearing capacity.
[0024] In order to make the objectives, features, and advantages
mentioned above of the present disclosure more apparent and easily
understood, the present disclosure will be further described in
detail below with reference to the drawings and particular
implementations.
Embodiment 1
[0025] As shown in FIG. 1, the present embodiment provides a
redundant parallel mechanism with less actuation and
multi-degree-of-freedom outputs 100, including: a fixed platform 1,
a moving platform 2, multiple moving branch chains 4, and one or
more redundant branch chains 3. Two ends of each moving branch
chain 4 are respectively connected to the fixed platform 1 and the
moving platform 2, and a brake 406 is arranged on each moving
branch chain 4. Two ends of each redundant branch chain 3 are
respectively connected to the fixed platform 1 and the moving
platform 2, and an actuating part 306 is arranged on each redundant
branch chain 3. Specifically, the number of the moving branch
chains 4 is greater than that of the redundant branch chains 3. It
can be seen that, in the present embodiment, based on a normal
non-redundant parallel mechanism, one or more (denoted as n)
redundant branch chains 3 are added to construct a redundant
parallel mechanism. The actuating part 306 is added to each of the
added redundant branch chains 3, and an actuating joint on each
original branch chain of the normal non-redundant parallel
mechanism is replaced with the brake 406, so that the original
branch chains become the moving branch chains 4 that can be locked
or follow up.
[0026] The number of the redundant branch chains 3 is set to n.
During control, the number of follow-up moving branch chains 4 is
set to n. Excepting for the follow-up moving branch chains 4 , the
other moving branch chains 4 are locked by the respective brakes.
The n follow-up moving branch chains move to expected positions and
postures under the control of the n redundant branch chains 3,
specifically, under the control of the actuating parts 306. Through
multiple adjustments, all moving branch chains 4 move to the
expected positions and postures. That is, the control of the
outputs of all expected degrees of freedom of the parallel
mechanism can be realized. It can be seen that the redundant
parallel mechanism of some embodiments has large bearing capacity,
the actuating parts 306 thereof are decreased, the cost thereof is
reduced, thereby realizing multidimensional independent outputs
through multiple actuating, further realizing the adjustment of the
position and posture of the mechanism, reducing the control
difficulty and simplifying the control of a redundant parallel
mechanism. Therefore, the mechanism has a very broad application
prospect.
[0027] Specifically, the redundant branch chain 3 includes a first
connecting piece 303, a first upper connecting rod 301, a second
connecting piece 304, a first lower connecting rod 302, and a third
connecting piece 305 connected in sequence from top to bottom. The
upper end of the first upper connecting rod 301 is connected to the
moving platform 2 through the first connecting piece 303. The lower
end of the first lower connecting rod 302 is connected to the fixed
platform 1 through the third connecting piece 305.
[0028] Specifically, the moving branch chain 4 includes a fourth
connecting piece 403, a second upper connecting rod 401, a fifth
connecting piece 404, a second lower connecting rod 402, and a
sixth connecting piece 405 connected in sequence from top to
bottom. The upper end of the second upper connecting rod 401 is
connected to the moving platform 2 through the fourth connecting
piece 403. The lower end of the second lower connecting rod 402 is
connected to the fixed platform 1 through the sixth connecting
piece 405.
[0029] The present embodiment further provides a control method for
the redundant parallel mechanism with less actuation and
multi-degree-of-freedom outputs 100, including the following steps:
n redundant branch chains 3 are provided. Firstly, the brakes 406
on the first n moving branch chains 4 are released, so that the
first n moving branch chains 4 is in the follow-up state, and the
brakes 406 of the other moving branch chains 4 are locked, so that
the other moving branch chains 4 are in a locked state. And, the
displacements of the first n moving branch chains 4 are able to be
adjusted by controlling the actuating input of the n redundant
branch chains 3. Then, the n+1th to 2nth moving branch chains 4 are
set to in the follow-up state, and the remaining moving branch
chains 4 are locked, so that the displacements of the n+1th to 2nth
moving branch chains 4 are able to be adjusted by controlling the
actuating input of the n redundant branch chains 3. And thus, the
adjustments of all moving branch chains 4 can be realized by
repeating above steps.
[0030] In the present specific embodiment, both the first
connecting piece 303 and the third connecting piece 305 are
spherical joints. The second connecting piece 304 is a prismatic
joint. The actuating part 306 is mounted on the second connecting
piece 304. The actuating part 306 is a linear actuating unit. That
is to say, the redundant branch chain 3 in the present embodiment
is an SPS (Spherical-Prismatic-Spherical) redundant branch chain,
and the actuating part 306 is added to a prismatic joint of the
redundant branch chain 3. The lower end of the first upper
connecting rod 301 is connected to the upper end of the first lower
connecting rod 302 through the prismatic joint. The upper end of
the first upper connecting rod 301 and the lower end of the first
lower connecting rod 302 are respectively connected to the moving
platform 2 and the fixed platform 1 through spherical joints. The
linear actuating unit is mounted on a prismatic joint of the
redundant branch chain 3. Specifically, the linear actuating unit
is a linear motor or a hydraulic cylinder.
[0031] In the present specific embodiment, both the fourth
connecting piece 403 and the sixth connecting piece 405 are
spherical joints. The fifth connecting piece 404 is a prismatic
joint. The brake 406 is mounted on the fifth connecting piece 404.
That is, the moving branch chain 4 in the present embodiment is an
SPS moving branch chain. A controllable brake 406 is added to the
prismatic joint of the moving branch chain 4, so that the moving
branch chain can be locked or follow up. The lower end of the
second upper connecting rod 401 is connected to the upper end of
the second lower connecting rod 402 through the prismatic joint.
The upper end of the second upper connecting rod 401 and the lower
end of the second lower connecting rod 402 are respectively
connected to the moving platform 2 and the fixed platform 1 through
a spherical joint. The brake 406 is mounted on a prismatic joint of
motion branch chain 4.
[0032] In the specific embodiment, six moving branch chains 4 are
provided, and one redundant branch chain 3 is provided, so as to
form a 7-SPS parallel mechanism with a single actuation and
six-degrees-of-freedom outputs.
[0033] A specific control process is as follows. The brake 406 on a
first moving branch chain 4 is released, and the brakes 406 on the
other five moving branch chains 4 are locked. The first moving
branch chain 4 follows up the redundant branch chain 3 by
controlling the actuating input of the redundant branch chain 3,
and the first moving branch chain 4 can be controlled to reach a
predetermined position. The brake 406 on a second moving branch
chain 4 is released, and the brakes 406 on the other five moving
branch chains 4 are locked. The second moving branch chain 4
follows up the redundant branch chain 3 by controlling the
actuating input of the redundant branch chain 3, and the second
moving branch chain 4 can be controlled to reach a predetermined
position. By repeating the above steps six times, the mechanism may
be controlled to reach the predetermined position.
Embodiment 2
[0034] As shown in FIG. 2, difference between the Embodiment 2 and
Embodiment 1 is the number of the redundant branch chains 3.
Specifically, there are two redundant branch chains 3 arranged in
the Embodiment 2 to form an 8-SPS parallel mechanism with two
actuations and six-degrees-of-freedom outputs.
[0035] A specific control process is as follows. The brakes 406 on
the first and second moving branch chain 4 are released, and the
brakes 406 on the other four moving branch chains 4 are locked. The
first and second moving branch chains 4 follow up the two redundant
branch chains 3 by controlling the actuating input of the two
redundant branch chains 3, and the first and second moving branch
chains 4 can be controlled to reach predetermined positions. The
brakes 406 on the third and fourth moving branch chains 4 are
released, and the brakes 406 on the other four moving branch chains
4 are locked. The third and fourth moving branch chains 4 follow up
the two redundant branch chains 3 by controlling the actuating
input of the two redundant branch chains 3, and the third and
fourth moving branch chains 4 can be controlled to reach
predetermined positions. By repeating the above steps three times,
the mechanism may be controlled to reach the predetermined
position.
Embodiment 3
[0036] As shown in FIG. 3, the difference between the Embodiment 3
and Embodiment 1 is the specific structure and the number of the
moving branch chains 4. Specifically, the fourth connecting piece
403 is a spherical joint. The fifth connecting piece 404 is a
prismatic joint. The sixth connecting piece 405 is a revolute
joint. The brake 406 is mounted on the fifth connecting piece 404.
That is, the moving branch chain 4 in the Embodiment 3 is an RPS
(Revolute-Prismatic-Spherical) moving branch chain. A controllable
brake 406 is added to the prismatic joint of the moving branch
chain 4, so that the moving branch chain can be locked or follow up
the redundant branch chain 3. The lower end of the second upper
connecting rod 401 is connected to the upper end of the second
lower connecting rod 402 through the prismatic joint. The upper end
of the second upper connecting rod 401 is connected to the moving
platform 2 through a spherical joint. The lower end of the second
lower connecting rod 402 is connected to the fixed platform 1
through the revolute joint. The brake 406 is mounted on the
prismatic joint of the moving branch chain 4.
[0037] In the Embodiment 3, three moving branch chains 4 are
provided, and one redundant branch chain 3 is provided, so as to
form a 3-RPS-SPS parallel mechanism with a single actuation and
two-rotation and one-movement outputs.
[0038] A specific control process is as follows. The brake 406 on
the first moving branch chain 4 is released, and the brakes 406 on
the other two moving branch chains 4 are locked. The first moving
branch chain 4 follows up the redundant branch chain 3 by
controlling the actuating input of the redundant branch chain 3,
and the first moving branch chain 4 can be controlled to reach a
predetermined position. The brake 406 on the second moving branch
chain 4 is released, and the brakes 406 on the other two moving
branch chains 4 are locked. The second moving branch chain 4
follows up the redundant branch chain 3 by controlling the
actuating input of the redundant branch chain 3, and the second
moving branch chain 4 can be controlled to reach a predetermined
position. By repeating the above steps three times, the mechanism
may be controlled to reach the predetermined position.
Embodiment 4
[0039] As shown in FIG. 4, the difference between the Embodiment 4
and Embodiment 1 is the structure and the number of the moving
branch chains 4, and the structure of the redundant branch chain 3.
Specifically, this Embodiment further includes a restraint branch
chain 5. The lower end of the restraint branch chain 5 is fixedly
connected to the center of the fixed platform 1. The upper end of
the constraint branch chain 5 is connected to the center of the
moving platform 2 through an universal joint. Both the first
connecting piece 303 and the fourth connecting piece 403 are
spherical joints. Both the second connecting piece 304 and the
fifth connecting pieces 404 are universal joints. Both the third
connecting piece 305 and the sixth connecting piece 405 are
revolute joints. The actuating part 306 is mounted on the third
connecting piece 305. The actuating part 306 is a rotary actuating
unit. The brake 406 is mounted on the sixth connecting piece
405.
[0040] Specifically, the lower end of the first upper connecting
rod 301 is connected to the upper end of the first lower connecting
rod 302 through an universal joint. The upper end of the first
upper connecting rod 301 is connected to the moving platform 2
through the spherical joint. The lower end of the first lower
connecting rod 302 is connected to the fixed platform 1 through the
revolute joint. The rotary actuating unit is mounted on the
revolute joint of the redundant branch chain 3. The lower end of
the second upper connecting rod 401 is connected to the upper end
of the second lower connecting rod 402 through an universal joint.
The upper end of the second upper connecting rod 401 is connected
to the moving platform 2 through a spherical joint. The lower end
of the second lower connecting rod 402 is connected to the fixed
platform 1 through the revolute joint. The brake 406 is mounted on
the revolute joint of the moving branch chain 4. That is, the
redundant branch chain 3 in the Embodiment 4 is a RUS
(Revolute-Universal-Spherical) redundant branch chain. A rotary
actuating unit is added to the revolute joint of the redundant
branch chain 3. The moving branch chains 4 are RUS moving branch
chains. A controllable brake 406 is added on each of the revolute
joints of the moving branch chains 4, so that the moving branch
chains can be locked or follow up the redundant branch chain 3.
Meanwhile, in the Embodiment 4, a restraint branch chain with an
universal joint is further included. Specifically, the rotary
actuating unit is a rotary motor.
[0041] In the Embodiment 4, two moving branch chains 4 are
provided, one redundant branch chain 3 is provided, and one
restraint branch chain 5 is provided, so as to form a 3-RUS-U
parallel mechanism with a single actuation and two-rotation
outputs.
[0042] A specific control process is as follows. The brake 406 on
the first moving branch chain 4 is released, and the brake 406 on
the second moving branch chain 4 is locked. The first moving branch
chain 4 follows up the redundant branch chain 3 by controlling the
actuating input of the redundant branch chain 3, and the first
moving branch chain 4 can be controlled to reach a predetermined
position. The brake 406 on the second moving branch chain 4 is
released, and the brake 406 on the first moving branch chain 4 is
locked. The second moving branch chain 4 follows up the redundant
branch chain 3 by controlling the actuating input of the redundant
branch chain 3, and the second moving branch chain 4 can be
controlled to reach a predetermined position. That is, the
mechanism may be controlled to reach the predetermined
position.
[0043] It should be noted that, in addition to the three types of
parallel mechanisms in the Embodiment 1 to Embodiment 4, the
redundant parallel mechanisms with less actuation and multiple
outputs, which are formed on the basis of other types of parallel
mechanisms by similar methods, are within the scope of protection
of the disclosure.
[0044] Specific embodiments are used in this specification for
illustration of the principles and implementations of the present
disclosure. The description of the above embodiments is merely used
to help understand the method and core concept of the present
disclosure. In addition, those of ordinary skill in the art may
make modifications to the specific implementations and application
scope in accordance with the concept of the present disclosure. In
conclusion, the content of this specification should not be
construed as a limitation to the present disclosure.
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